Regulated high voltage supplies



June 5, 1956 J. o. PREISIG 2,

REGULATED HIGH VOLTAGE SUPPLIES Filed June 29, 1954 2 Sheets-Sheet l 11F1 YiiC/t z :04 55 F2 yew/z z PULSE $0036! I N V EN TOR. JOSE H aP/FE/S/' J. o. PRElSlG REGULATED HIGH VOLTAGE SUPPLIES June 5, 1956 2Sheets-Sheet 2 Filed June 29, 1954 INVENTOR. J05! 0. FEELS/6 BY &

iTToR/VE REGULATED marl VOLTAGE SUPPLIES Joseph 0. Preisig, Trenton, N.J., assignor to Radio Corporation of America, a corporation of DelawareApplication June 29, 1954, Serial No. 440,067

8 Claims. (Cl. 315-14) This invention relates generally to theregulation of voltage supplies and more particularly to novelimprovements in the regulation of voltage supplies of the type suitablefor satisfying the high voltage requirements of cathode ray tubeelectrodes.

It has become more or less a general practice in the monochrometelevision art to obtain the high voltage required for the finalaccelerating electrode of a receivers kinescope from a pulse typesupply, in which high voltages are developed through rectification ofthe high amplitude, transient, fiyback pulses appearing in the receivershorizontal output transformer during retrace periods of the linescanning cycle, when cutoff of the horizontal output tube causes asudden collapse of the magnetic field in the horizontal deflection yoke.Similarly, the development of high voltages for the final acceleratingelectrode, or so-called ultor electrode, of presently contemplated colorkinescopes has been considered as calling for the use of such fiybackpulse type supplies. However, the high voltage requirements of a typicalcolor kinescope are greater in magnitude, more critical as toregulation, and generally more demanding than the comparable supplyrequirements of a monochrome kinescope. It has thus been generallyrecognized that the ultor supply for a color kinescope requires the useof an active voltage regulating device to achieve the requisitestability of the supplied ultor voltage. The present invention isdirected toward improved apparatus for, and methods of, regulating thehigh voltage supply of a color receiver to eliminate or substantiallyreduce certain deleterious effects which may result from variations inthe supply output.

To more particularly appreciate the purposes of the present invention,as well as its form, a brief description of a conventional colorkinescope ultor supply is in order. In a representative type of highvoltage supply for a tri-color kinescope of the general type describedin the article by H. B. Law entitled A Three-Gun Shadow-Mask ColorKinescope, appearing in the October 1951 issue of the Proceedings of theI. R. E., stepped-up fiyback pulses derived from the horizontaldeflection wave output transformer are applied to the input electrode ofa rectifier, which may take the form of a high voltage vacuum diode, forexample. The rectifier delivers a charging current to a capacitor,connected between the output electrode of the rectifier and a suitablepoint of reference potential, in response to the periodic appearance offiyback pulses. The D.-C. voltage developed across the chargingcapacitor is applied to the kinescopes ultor electrode, which may bedirectly connected to the rectifiers output electrode. Since theeffective loading on the ultor supply will necessarily vary with picturecontent (i. e. with beam current), D.-C. regulation is generallyrequired and achieved by shunting the space discharge path ofa regulatortube across the rectifier output circuit, and deriving an error orreference potential for the control electrode of the regulator tube2,749,474 Patented June 5, 1956 ICC from a bleeder resistance, alsoshunted across the rectifier output circuit. In such supplies, the shuntregulator tube essentially functions only to effect D.-C. regulation,that is, only to remove relatively long term variations in the suppliedultor voltage. The regulator control circuit is essentially by-passedfor shorter term, A.-C. variations in the supplied voltage, the chargingcapacitor being variations to the reference potential point.

The A.-C. variations in the supplied voltage may be considered as causedby two efifects, one being the residual 60 cycle ripple in the D.-C.output of the rectifier due to the use of periodic pulses as the energysource for the supply. To appreciate the other cause of A.-C. variationsin the supply output, it must be recognized that a kinescope, whileintended primarily as an image reproducing device, is also effectively avideo signal amplifier, the ultor electrode serving as the anode for thevideo-modulated grid-controlled beam current. While appropriate choiceof the value of the supplys filter capacitor may reduce the effect ofvideo signal variations to relatively small percentage changes in thehigh voltage output, the expense of providing suitably insulated highvoltage capacitors of high capacitance value introduces an economicfactor which must be considered. In typical high voltage power suppliesof the prior art, the value of the filter capacitor has been chosen,with an eye to this cost factor, of a value such that the capacitorpresents a sutficiently low impedance to most video signal frequenciesso that the output variations at these frequencies are relativelyinsignificant. At low video signal frequencies, such as frequencies ofthe order of the 60 cycle field scanning rate, however, the impedence ofthe typical ultor supply filter capacitor is sufficiently high thatoutput variations of the order of several per cent are possible inresponse to the presence of video signal components of such frequenciesin the beam modulating signal. While variations of such an order in thepotential of the ultor electrode may be tolerable, another efiect whichis less tolerable is also a result.

The other effect noted above is a beam rnisconvergence efiect, whichresults from the fact that where supplies of the type discussed aboveare used for tri-color kinescopes incorporating beam convergenceapparatus of an electrostatic type, it has been the practice to derivethe D.-C. (static) convergence voltage required by the kinescopesconvergence anode from the aforesaid output bleeder of the ultor supply.The problems of beam convergence in color image reproducers arediscussed in some detail in the article entitled Deflection andConvergence in Color Kinescopes by Albert W. Friend, also appearing inthe aforementioned October 1951 issue of the Proceedings of the I. R. E.It may be appreciated by those familiar with beam convergence problemsthat the permission of the aforesaid low frequency A.-C. variations inthe ultor supply voltage, appearing across the bleeder to which theconvergence anode is coupled, will result in the application ofundesired dynamic convergence voltage variations to the beam convergenceanode. The re sultant rnisconvergence effects, while certainly notwholly destructive of the fidelity of the color image reproductioneffected by the color kinescope, may be annoying and undesirable, andtheir elimination should result in the production of a more pleasingcolor picture.

As will be appreciated from the previous discussion, a reduction inthese rnisconvergence effects may be achieved by increasing thecapacitance value of the filter capacitor employed in theultor-convergence supply, so asto more effectively short out the lowvideo frequency signals. However, it will again be appreciated thatachievement of a substantial elimination of these rnisconvergenceeffects in such a manner might involve a considerable added expense, asrepresented by the increase in cost of the high voltage capacitorutilized.

In accordance with the present invention, however, means forsubstantially eliminating these misconvergence effects are proposed,whereby such expense as involved in providing a filter capacitor ofrelatively high capacitance value is avoided. In accordance withembodiments of the present invention, such a result is achieved throughutilizing the shunt regulator tube of the ultor supply for A.-C.regulation purposes as well as D.-C. regulation purposes. Morespecifically, the usual filter capacitor is supplanted by a capacitor ofcomparable value which couples the ultor voltage output to the controlelectrode of the shunt regulator tube so as to achieve a degeneration ofthe aforesaid video signal variations in the output. This capacitor, inseries with the usual bias filter capacitor associated with theregulator tube, provides the requisite charging path for the ultorrectifier current, and achieves the filtering function normally effectedby the filter capacitor which they supplant. The values of the twoseries capacitors are preferably chosen with respect to the resistancevalues of the portions of the bleeder which they shunt (i. e. thebleeder portions on either side of the regulator sampling tap) toprovide substantially equal time constants, so that a constant ratiodivision of the AC. signals is effected at the regulator controlelectrode for all video signal frequencies. Elimination ofrnisconvergence effects due to the coupling of video signal componentsto the convergence anode of a color kinescope via the output circuit ofthe ultor supply is thus achieved without increasing the cost of theconventional ultor supply.

Accordingly, it is a primary object of the present invention to providea novel regulated high voltage supply.

It is an additional object of the present invention to provide novelmeans to eliminate misconvergence eifects in the operation of a colorkinescope resulting from the ap pearance of video signal variations inthe supply output from which the D.-C. convergence voltage is derived.

It is a further object of the present invention to pro vide a novel highvoltage supply for a color lcinescope in which both short term and longterm variations of the supply output are regulated out.

It is also an object of the present invention to provide a colortelevision receiver with a novel and improved high voltage supply inwhich a shunt regulator tube eifectively functions as both a D.-C. andan A.-C. regulator.

Another object of the present invention is to improve the regulation ofconventional high voltage supplies for a color kinescope withoutincrease in the expense thereof.

Other objects and advantages of the present invention may be ascertainedby those skilled in the art upon a reading of the following detaileddesscription and an inspection of the accompanying drawing in which:

Figure 1 illustrates schematically a high voltage supply suitable forcolor kinescope purposes, in which regulation is achieved in accordancewith prior art principles.

Figure 2 illustrates schematically such a high voltage supply asregulated in accordance with principles of the present invention.

Figure 3 illustrates the use of a high voltage supply in accordance withan embodiment of the present invention in a typical color televisionreceiver.

Referring to Figure 1 in more detail, a high voltage supply of a typeused prior to the present invention for supplying the ultor andconvergence electrodes of a color kinescope is illustrated. Highamplitude flyback pulses, appearing at terminal Z of a fiyback pulsesource 11, which may comprise the horizontal deflection wave outputtransformer of the color receiver, are applied to the anode 14 of adiode rectifier 13. The cathode 15 of diode 13 is directly connected tothe supply output terminal U, to which the ultor electrode of the colorkinescope may be coupled, and is coupled to a point of referencepotential (i. e. ground in the illustration) by a charging capacitor 17.A charging current is delivered by rectifier 13 to capacitor 17 inresponse to the periodic appearance of fiybaclt pulses at terminal Z,developing a DC. potential across capacitor 17 which is utilized by theaforesaid ultor electrode as its operating potential.

To eifect the requisite D.-C. regulation of the supply output, the spacedischarge path of a regulator tube, triode 19, is effectively shuntedacross the ultor supply output, the anode 21 of triode 19 beingconnected to the output terminal U and the cathode 25 being connected tothe high potential terminal of a suitable B+ supply (not illustrated).An error or reference potential, for controlling the current in thespace discharge path of regulator tube 19 in accordance with variationsin the D.-C. voltage supplied to the ultor electrode, is applied to thecontrol grid 23 of regulator 19 via its coupling to the adjustable tapof a potentiometer 32, which forms a series resistance portion of a highvoltage bleeder 7.9, also shunting the ultor supply output. The D.-C.(static) convergence voltage required by the convergence anode of thecolor kinescopc (employing electrostatic convergence methods) is alsocommonly derived from the high voltage bleeder 29, as by coupling theconvergence supply output terminal (1" to the adjustable tap ofpotentiometer 31 which forms another series resistance portion of thebleeder 29. It will be noted that in accordance with common practice, abias filter capacitor 27 is coupled between the control grid 23 andcathode 25 of the regulator tube 19.

In Figure 2, application of the principles of the present invention tothe prior art supply of Figure l is illustrated. Again, the anode 14 ofrectifier 13 is connected to the terminal Z of the fiyback pulse source11, and cathode 15 is connected to the supply output terminal The spacedischarge path of regulator tube 19 is again effectively shunted acrossthe ultor supply output, and its control grid 23 is again coupled to theadjustable tap of potentiometer 32 forming a series resistance portionof the output-shunting high voltage bleeder 29. It will be noted,however, that the usual coupling of a capacitor 17 between the cathode15 and a point of reference potential is not effected. instead, acapacitor 17 is coupled between rectifier cathode 15 and the controlgrid 23 of the rcgulator tube 19. The bias filter capacitor 27 isillustrated as being coupled between the control grid 23 and ground. Itwill be noted that the circuit of Figure 2 contains no additionalcircuit elements over those shown in Figure l. However, there are markedadvantages to the use of the circuit connections illustrated in Figure 2over the prior art connections illustrated in Figure l, which shall nowbe noted.

In the supply circuit illustrated in Figure l, the regulator tube 19eiiectively functions only as a D.-C. regulator, overcoming relativelylong term variations in the output voltages supplied. The chargingcapacitor 17 is intended to also serve as filter capacitor. effectivelyshorting video signals appearing at terminal U (due to the previouslydiscussed video signal amplifying action of the color kinescope) toground. As previously noted, however, unless a high voltage capacitor ofrelatively high capacitance value is utilized as capacitor 17, thefiltering action of capacitor 17 is not too effective at the low end ofthe video signal frequency range. That is, the impedance of capacitor 17at low video signal frequencies, of the order of the cycle fieldscanning rate, for example, is sutficiently high that significantvariations in the supply output may occur. If the A.-C. variations areof the order of, say, two percent of the nominal ultor voltage value,such A.-C. changes in the potential of the ultor electrode may bereadily tolerable. but a more serious result resides in the resultantvariations in the voltage supplied to the convergence electrode of thecolor kinescope. Since the convergence electrode is coupled. to theultor supply output via the high voltage bleeder 29, ultor voltagevariations of the aforesaid. order result effectively in the applicationof an undesired dynamic convergence voltage waveform which may introducesignificant misconvergence efiects. While suitable increase of thecapacitance of filter capacitor 17 to a value at which its filteringaction at the low end of the video signal frequency range is sufficientto reduce these misconvergence effects to a tolerable level is onesolution, this is an unduly expensive solution in view of the manner inwhich the present invention proposes to eliminate such deleteriouseffects.

The solution as envisaged by the present invention and illustrated inFigure 2 is to utilize the regulator tube 19, already present in thecircuit and performing a D.-C. regulating function, to degenerate orregulate out the aforesaid video signal variations. By capacitivelycoupling the video signals which appear at anode 21 to the control grid23 also, such degeneration is effected. The capacitor 17, efiecting thisdesired coupling, may also serve, in series with the bias filtercapacitor 27, to provide the charging path required for the ultorrectifier 13. It may be observed that the capacitors 17 and 27efiectively provide a capacitance voltage divider for applying apredetermined fraction of the A.-C. signal variations to the controlgrid 23, similar to the D.-C. voltage division effected by the tappingof bleeder 29 for connection to control grid 23. The capacitance valuesof capacitors l7 and 27 are preferably chosen with relation to theresistance portions of the bleeder 29 that they shunt (i. e. R1 and R2,respectively) so that the time constants, R1 C17 and R2 C27 aresubstantially equal. With such a relationship, it will be appreciatedthat the ratio of the A.-C. signal variations applied to control grid 23to the A.-C. signal variations appearing at terminal U will besubstantially constant at all frequencies, the ratio corresponding tothe D.-C. voltage division effected at the tap connection of controlgrid 23 to bleeder 29. It may be observed that in addition to effectinga degeneration of the video signals amplified by the kinescope, theA.-C. regulating arrangement of Figure 2 aids in degenerating ripplecomponents which may inhere in the output of the rectifier 13.

Figure 3 illustrates a color television receiver including a highvoltage supply which operates in accordance with the embodiments of thepresent invention discussed above.

The illustrated receiver is generally representative of presentlycontemplated color receivers for a simultaneous subcarrier type colortelevision system in accordance with the revised FCC color standards,and is in general accord with the principles and apparatus discussed inthe article entitled Principles and Development of Color TelevisionSystems, by G. H. Brown and D. G. C. Luck appearing in the June 1953issue of the RCA Review. Carrier waves modulated by a composite colorpicture signal are received by conventional signal receiving apparatus61, which may include the usual R. F. tuner, converting apparatus, I. F.amplifier, signal detector, etc. The video frequency signals recoveredfrom the modulated carrier in the receiving apparatus 61 are amplifiedin the video amplifier 63. Synchronizing information is derived from therecovered signals in the sync separator 65 and utilized to synchronouslycontrol the receivers subcarrier drive apparatus 67, to control thegeneration of vertical scanning waves in the vertical deflectioncircuits 69, and control the generation of horizontal frequency sawtoothvoltage waves in the horizontal sawtooth wave generator 71.

Respective color mixture signals (e. g. narrow band E signals and widerband Er signals, discussed in detail in the aforementioned article) arerecovered from the video signal output of amplifier 63 in respectivecolor demodulator channels which include bandpass filters 75 and 77 ofrespectively appropriate passbands, synchronous demodulators 81 and 83receiving respectively appropriate phases of the output of thesubcarrier drive apparatus 67, and low pass filters 85 and 87 having therespectively appropriate narrow and wider responses. The receiver isalso provided with a brightness channel, including a low pass filter 86having the desired wide band response, through which the broad bandmonochrome portion of the composite picture signal may pass. The outputsof the brightness channel and two color channels are suitably combinedin the matrixing circuits 89 of the receiver to obtain the simultaneouscolor sig nals which may be applied to appropriate beam control elementsof the color image reproducer 40.

The color image reproducer 40 is illustrated schematically as one of thethree-gun shadow-mask kinescope type. Color image reproducers of thisgeneral type are discussed in some detail in the aforementioned articleby H. B. Law entitled A Three-Gun Shadow-Mask Kinescope. In a colorimage reproducer of this type, three electron beams are used, one foreach primary color. The beams strike a phosphor screen composed of aregular array of red-, green-, and blue-emitting phosphor dots. Betweenthe electron gun position and the phosphor screen there is placed a thinperforated metal sheet for the purpose of partially masking the electronbeams. The phosphor dot array on the screen comprises a plurality ofclosely spaced phosphor dot trios, each trio consisting of a red-,green-, and blue-emitting phosphor dot with the centers of the dotslying at the corners of an equilateral triangle. The trios themselveslie at the corners of an equilateral triangle of larger size. Associatedwith each of the phosphor dot trios is a hole in the shadow mask, theseholes also being located at the corners of an equilateral triangle. Thethree beams, disposed apart about the tube axis, are converged to apoint on the mask by suitable static and dynamic beam converging means,the electron beam which is to contribute the red portion of the pictureis prevented, by the mask, from striking those areas on the screencontaining blue and green emitting phosphors. Likewise the green andblue beams can strike only the green and blue emitting phosphor dots,respectively. The target structure 51 of the illustrative colorkinescope 40 may be considered to be of the general shadow-mask typeabove described.

As schematically illustrated, the three electron beams are developed andshaped in respective electron gun structures, each including athermionic cathode 41, a control grid 43, a first anode or acceleratingelectrode 45, and a focusing electrode 47. The electron gun structuresmay be disposed symmetrically about the tube axis such as to producethree substantially parallel beams or may be inclined at respectiveangles to the tube axis so as to provide three beams substantiallyconverging at a common point on the target.

A common convergence anode 49 is illustrated, which when energized bysuitable dynamic convergence waveforms generated in the dynamicconvergence waveform generator 56 along with an appropriate (staticconvergence) D.-C. component, serves to converge the three beams to acommon point in the plane of the shadowrnask of target structure 51throughout the scanning of the raster. The principles of multibeamconvergence, and a description of typical circuits for developingdynamic convergence waveforms from sawtooth waves of field and linefrequency may be found in an article by Albert W. Friend appearing inthe October 1951 issue of the Proceedings of the I. R. E. and entitledDeflection and Convergence in Color Kinescopes. As illustrated, the beamconvergence circuits may derive the respective sawtooth information fromthe vertical deflection circuits 19 and the horizontal outputtransformer 93, and convert these sawtooth Waves into essentiallyparabolic waveforms, as disclosed in the aforementioned Friend article,for combined application with a D.-C. component as suitable convergencewaveforms to the common convergence electrode 49. Also, as indicated inFigure 3, the correcting waveform output of generator 56 may be applied,suitably modified in amplitude, to the focus electrodes 47 to maintainessentially optimum focus throughout the entire raster, as suggested inthe Friend article. Beam alignment magnets 57, one associated with eachof the three electron beams, may be employed to provide individualcorrection of beam misalignment, as disclosed in the aforementionedFriend article.

In addition to the beam controlling apparatus already described, theillustrated color kinescope 4t is also provided, as is generallycustomary, with a color purity yoke 54, applying a uniform transversemagncdc field to all the electron beams to orient the system of beams asdesired. The yoke may comprise either a rotatable single pair of coils,or two fixed pairs of coils at right angles, fed from an adjustablesource of D.-C. (as indicated on the drawing). The use of such a puritycoil to deflect the three beams equally so that they may be adjusted topass through their respective color centers is explained in greaterdetail in the aforesaid Friend article.

The kinescope is provided, as is conventional, with a final acceleratingelectrode, the ultor 50, which may take the usual form of a conductivecoating on the inner surface of the lrinescope 46 extending from thevicinity of the convergence electrode 4? to the beam target structure52. Where the flared portion of the kinescope envelope is itself aconducting metal, the conductive coating need only extend forwardsufficiently to make electrical contact with the metal flared portion.

To effect deflection of the three beams to trace a scanning raster n thetarget structure 51., a deflection yoke 53 is provided withappropriately disposed hori Zontal and vertical deflection windings. Theyoke 53 is illustrated as having vertical yoke terminals V--V, to whichfield frequency scanning waves developed in the vertical deflectioncircuits as are applied. The horizontal yoke terminals I-L-Ii deriveline frequency scanning waves from the horizontal output transformer 93,energized by a current supplied by the horizontal output tube 91 toprovide the desired scanning sawtooth in the horizontal yoke. Theillustrated horizontal. output trans former 93 is of the autotransformertype, the cutout ot' the horizontal output tube 91 being applied acrossa selected portion of the total series of windings, and the horizontalyoke being effectively coupled across a smaller segment of this portion.The driving connection output tube 91 to the transformer $3 isillustrated as being at an intermediate point Y, while the yokeconnections are illustrated at lower potential terminals R and on thetransformer 93. The conventional danger tube 92 is illustrated as havingits cathode connected to trans former 93 at point T. intermediate pointsS and Y," and its anode connected via a B-boost capacitor 94 to the lowpotential terminal R. Details of components and circuitry conventionallyassociated with yoke circuits, such as width and linearity controls,centering circuits, etc. have not been illustrated for the sake ofsimplifying the drawing.

The high voltage supply illustrated in Figure 3 as associated with thehorizontal output transformer 93, in cludes a conventional focus supplyarrangement. in which the focus rectifier Edi is coupled to anintermediate point X on the output transformer 3. The D.-C. output ofrectifier Kill, appearing across the capacitor 103, is applied acrossthe fixed terminals of potentiometer U35. The focus supply outputterminal F, to which the focus electrodes 47 of itinescope 4% arecoupled, is connected to a variable tap on potentiometer 195, so thatadjustment of the voltage supplied to the focus electrodes may be made.

The ultor-convergence voltage supply arrangement illustrated in Figure 3is in accordance with the embodiment of the invention illustrated inFigure 2. The anode 14 of the ultor rectifier 13 is connected to thehigh potential terminal Z of the output transformer 93. The

ultor supply output terminal U is connected to cathode 15 of rectifier13. The space discharge path of regulator tube 19 shunts the output ofultor rectifier 13, and derives its D.-C. reference potential via thecoupling of control grid 23 to the variable tap of the potentiometer 32portion of a high voltage bleeder 29, also shunting the ultor rectifieroutput. The convergence supply output terminal C, to which theconvergence anode 49 is coupled, is connected to the variable tap on thepotentiometer 31 portion of bleeder 29.

in accordance with the principles of the present invention as previouslydiscussed, the capacitive charging path for rectifier 13 is provided bya series connection of capacitors 17' and 27' between terminal U andground. The regulator control grid 23 is connected to the junction pointbetween capacitors 17 and 27.

To review the advantages noted for this arrangement of the regulatedultor supply, it may be noted that video signal variations which appearat terminal U, and would otherwise tend to adversely affect beamconvergence, are effectively degenerated by the action of regulator tube19 due to the capac' ive coupling betwee. control grid 23 and terminalU. By appropriate proportioning of the values of capacitors 17 and 27, asatisfactory degree of degeneration may be achieved for all videofrequencies. Degeneration or ripple components in the pulse rectifieroutput is also effected. The 2vvantageous performance thus outlined maybe achieved without requiring additional tubes or circuit elements overthose used in prior art supplies 01? this general type.

Having thus described my invention, what is cla' ned is:

1. In a color television receiver including a color kinescope comprisingan ultor electrode, a high voltage supply .com-prising in combination arectifier having an output circuit, means for coupling said ultorelectrode to said output circuit, an electron discharge device having aspace discharge path and including a control grid, said space dischargepath effectively shunting said output circuit, and means forcapacitively coupling said ultor electrode to said control grid.

2. A high voltage supply in accordance with claim 1 including a bleederresistance also shunting said rectifier output circuit, and means foradjustably coupling said control grid to said bleeder resistance.

3. In a cathode ray tube system including a cathode ray tube devicecomprising an ultor electrode, a high voltage supply comprising incombination a rectifier having an output electrode, means for connectingsaid ultor electrode to said output electrode, an electron dischargedevice including an anode, a cathode and a control grid, means forconnecting said anode to said output electrode, means for connectingsaid cathode to a point of reference potential, a capacitor, and meansfor coupling said capacitor between said control grid and said ultorelectrade.

4. A high voltage supply in accordance with claim 3 including aresistance, means for connecting said resistance between said ultorelectrode and a point of reference potential, and means for connectingsaid control grid to an intermediate point on said resistance.

5. A high voltage supply in accordance with claim 4 including anadditional capacitor, means for connecting said additional capacitorbetween said control grid and said point of reference potential, theratio of the capacitance value of said first-mentioned capacitor to thecapacitance value of said additional capacitor being substantially equalto the ratio of the ohmic value of the pontion of said resistanceextending between said intermediate point and said point of referencepotential to the ohmic value of the portion of said resistance extendingbetween said intermediate point and said ultor electrode.

6. A voltage supply comprising in combination an energy source, arectifier having an input circuit and an output circuit, an outputterminal, means for coupling said input circuit to said energy source,means for coupling said output circuit to said output terminal, aregulator tube including a space discharge path and a control grid,means for shunting said space discharge path across said output circuit,a resistive voltage divider also shunted across said output circuit andincluding an intermediate tap, a capacitive voltage divider also shuntedacross said output circuit and having an intermediate terminal, andmeans for connecting said control grid to both said intermediate tap andsaid intermediate terminal.

7. In a color television receiver including a color kinescope comprisingan ultor electrode and a convergence electrode, a high voltage supplycomprising in combination an ultor rectifier having an output electrodecoupled to said ultor electrode; :an electron discharge device havingl3. space discharge path shunted across the output of said ultorrectifier and including a control electrode; means for utilizing saiddischarge device as a D.-C. regulator, said utilizing means comprising ahigh voltage bleeder also shunted across said ultor rectifier output,and means for adjustably coupling said control electrode to anintermediate point on said bleeder, said convergence electrode beingcoupled to a second intermediate point .On said bleeder; .and means foradditionally utilizing said discharge device as an A.-C. regulator, saidadditional utilizing means comprising a capacitor, and means forcoupling said capacitor between said control electrode and said ultorelectrode.

8. A high voltage supply in accordance with claim 7 including means forrendering the A.-C. regulating performance of said discharge deviceessentially independent of frequency, said latter means including anadditional capacitor, and means for coup-ling said additional capacitorbetween said control electrode and a point of reference potential, thesum of the capacitance values of said additional capacitor and saidfirst-mentioned capacitor bearing essentially the same relationship tothe capacitance value of said first-mentioned capacitor as the voltageappearing across said bleeder bears to the divided voltage appearing atsaid first intermediate point of said bleeder.

References Cited in the file of this patent UNITED STATES PATENTS2,215,766 Barnard Sept. 24, 1940 2,237,649 Blurnlein et 'al. Apr. 8,1941 2,276,455 Beers Mar. 17, 1942 2,352,988 Wilcox July 4, 19442,493,600 Seaward Jan. 3, 1950 2,523,108 Friend Sept. 19, 1950 2,599,798Wissel June 10, 1952 2,621,305 Little et al. Dec. 9, 1952 2,655,615Seldin Oct. 13, 1953

